Novel Label-Free GelRed-Aptamer Sensor for the Rapid Determination of Deoxynivalenol in Wheat Caused by Fusarium graminearum

Deoxynivalenol (DON) is the key virulence factor in Fusarium head blight. However, rapid and low-cost methods for DON are limited. Herein, a novel label-free GelRed-aptamer sensor was developed for the detection of DON. GelRed was embedded in double strain DNA (dsDNA) consisting of a single chain aptamer and its complementary DNA (cDNA), resulting in the increase of fluorescence intensity. However, DON preferentially combined with the aptamer and did not combine with its cDNA, which would result in the decrease in the formation of the GelRed/aptamer/cDNA complex, greatly reducing the fluorescence intensity. The samples were extracted from wheat, centrifuged, and filtered through a 0.22 μm membrane. Good linearity was obtained for DON from 3.13 to 313 mg L−1. The limit of quantitation (LOQ) for wheat samples was 6.07 mg L−1, providing a low cost method for DON compared with enzyme-linked immunosorbent assays. Experiments with spiked samples showed good recoveries from 92% to 105% with relative standard deviations less than 5.33% with analysis within 20 min. This method is simple and low cost with potential applications in agriculture and food.